This application is based on and incorporates herein by reference Japanese Patent Application No. 2002-18396 filed on Jan. 28, 2002.
The present invention relates to a connector which is used for an electric connection in an electronic control device installed in, for example, an engine room of an automobile. In particular, the invention relates to bonding areas of the connector.
In an engine room of an automobile, an electronic control unit (ECU) is provided to execute various controls for the automobile. The ECU is provided with a connector (for instance, a plastic connector) to connect the ECU with various external devices such as sensors or actuators.
The connector is electrically linked with a substrate within the ECU, for instance, by aluminum wires. The connector has a plurality of long metal contact terminals which penetrate the body of the connector. In a section connecting to the substrate within the ECU, planar connecting areas (bonding areas) formed on the ends of the contact terminals are exposed to be bonded with the aluminum wire.
Incidentally, recent requirements for miniaturization of the connector have reduced the spaces between the contact terminals (connector pitch) and made the aluminum wire thinner. These requirements restrict the choice of bonding direction.
Since the restriction in the connector pitch limits the width of the bonding area, the bonding direction must be in the longitudinal direction of the rectangular bonding area. Other directions are impractical, so that design flexibility is limited.
Such an existing design is shown in FIG. 8. To make an electric connection between a substrate P1 and a connector P2 with a narrow connector pitch, an end of a contact terminal P3 has a longitudinal bonding area P4. It is thus necessary for the bonding area P4 to be bonded by an aluminum wire P6 to a bonding area P5 of the substrate P1 in the longitudinal direction as shown.
Recent ECUs require relatively high permissible electric current capacity in the contact and relatively high electric current to carry the load of the ECU. A plurality of bonding wires are therefore necessary for connecting high current contacts (power pins) with the substrate; however, it is difficult to accomplish this due to the narrow contact spacing.
It is difficult for a load circuit, such as a solenoid which requires a larger circuit area, to be densely packed unlike a signal line connection, so that the circuit wires are likely to be relatively long. Long wires are undesirable due to an increase in resistance. However, under the above bonding restriction, the load circuit must have relatively long wires on the substrate and the power pin wires will be parallel with signal lines, which causes problems such as increased wiring resistance and restricted circuit layout.
An object of the present invention is to provide, even under condition of narrowing contact spacing, a connector in which restrictions regarding a bonding direction is reduced and flexibility of circuit layout is enhanced.
To achieve above object, the connector is provided with a relatively larger bonding area only in an outer periphery of a connecting section. The larger bonding area permits more than one bonding direction and increases the maximum number of wires that can be bonded to the bonding area. The outer location improves heat dissipation from the connecting section of the connector, so that the permissible electric current capacity is increased.